The present invention relates to a brake mechanism for stopping the rotation of a wire reel of a reinforcing bar binding machine after a binding wire of a redetermined length has been fed out from the wire reel.
In general, in a reinforcing bar binding machine, a binding wire of a predetermined length is wound round reinforcing bars crossing with each other, and then this binding wire is twisted by a twisting hook so that the reinforcing bars can be bound up. The binding wire is wound round a wire reel attached at the rear of the binding machine body. In the case of feeding the wire, it is fed forward by a wire feeding means. At this time, the wire reel is rotated, and the wire is fed out from the wire reel. A length of the wire to be fed out is accurately controlled. Therefore, when the wire of a predetermined length is fed out, the feed of the wire is suddenly stopped.
However, the following problems may be encountered in the above wire feeding mechanism. Although the feed of the wire is suddenly stopped when the wire of a predetermined length is fed out from the wire reel, the wire reel continues to rotate redundantly by the action of inertia of the wire reel. Therefore, a diameter of the wire wound round the wire reel is increased, and the wires are entangled with each other. As a result, it becomes impossible to feed out the wire smoothly, and problems may be caused when the wire is fed out in the next stage.
In order to take measures to solve the above problems, it is possible to apply the brake to the wire reel by a leaf spring at all times so that the inertial rotation of the wire reel can be prevented. However, the following problems may be caused in this case. A load necessary for feeding the wire is increased, and an electrical current consumption of the wire feeding motor is increased. As a result, the wire feeding motor is heated and the feeding speed is lowered.